This invention relates generally to switching amplifiers and more specifically to controlling output transistor saturation.
There are various switching amplifiers utilized for controlling large output currents for the control and operation of various large electrical equipment, such as linear induction motors where the load current and frequency are varied over a large range.
The efficiency of these devices depends on the efficiency of the output of the amplifier. Commonly available circuitry does not operate at maximum efficiency in that there is no control means for preventing the collector voltage of the output transistor from reaching a level less than the level of the base voltage and thus driving the transistor into saturation. This condition increases the power loss within the transistor by increasing its switching time.
A switching amplifier with an output transistor that could be maintained just at saturation at all times regardless of changing loads would find considerable commercial acceptance to improve its efficiency and reduce average drive power requirements.